Style fix: no semicolons after interface definitions!

In 894d0af (pushNotesRef: allow for concurrent operations, 2025-02-08),
I introduced an interface, but I got the syntax wrong... Typescript was
lenient, but ESLint isn't:

    gitgitgadget/tests/git-notes.test.ts
      128:6  warning  Delete `;`

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

tests/git-notes.test.ts

@@ -120,7 +120,7 @@ test("push()", async () => {
     interface O {
         hello: string;
         bye?: string;
-    };
+    }
     const o: O = { hello: "world" };
     await notes.set("", o);
     await notes.push(remoteRepo.workDir);